Method of introducing leak detection dye into an air conditioning or refrigeration system including solid or semi-solid fluorescent dyes

ABSTRACT

A method of introducing a leak detection dye into a closed refrigeration system through circulation of the refrigerant. A predetermined amount of the leak detection dye, which is soluble in the refrigerant and the system lubricant, is installed in a component of the refrigeration system, such as in a desiccant bag placed in a dehydrator. The leak detection dye may come in various forms including as a leak detection additive having the leak detection dye implanted on and absorbed into a host swatch of a substrate material, as a powder, as a solid pellet of powdered dye concentrate and inert ingredients, or as a slurry. The refrigeration system is assembled, charged and operated, by which the refrigerant and system lubricant flowing through the component, such as a desiccant bag in the dehydrator, and mixes the dye with the refrigerant and system lubricant.

This is a continuation-in-part of application Ser. No. 08/297,355, filedon Aug. 29, 1994, and issued as U.S. Pat. No. 5,440,919, on Aug. 15,1995.

FIELD OF THE INVENTION

This invention relates generally to the field of detecting leaks in anair conditioning or other refrigeration system and, more particularly,to improved methods of introducing a leak detection dye into the systemincluding the introduction of leak detection dyes into the system in asolid or semi-solid form.

BACKGROUND OF THE INVENTION

There has long been a need to locate leaks in closed refrigerationsystems, originally because the loss of refrigerant reduces the coolingcapacity of the system, and increasingly because the refrigerantsthemselves are potential hazardous or deleterious substances whenreleased to the atmosphere. In particular, the production and use ofchlorofluorocarbon (CFC) and hydrochlorofluorocarbon (HCFC) refrigerantsis scheduled for incremental phaseout, and for recovery and recycling inthe interim.

Various methods have been used for detecting and locating leaks in arefrigeration system. Since a slow leak of refrigerant is essentiallysilent and invisible, such methods have included halide torches,electronic sensors, coating exterior joints with material which reactswith the refrigerant, and injecting various types of dye into therefrigeration equipment to locate sites where the dye exits the system.

One of the most effective methods for detecting leaks in refrigerationsystems, and a preferred method to be practiced with the presentinvention, comprises infusing into the refrigeration system an effectiveamount of a fluorescent dye compound, dissolved either in the systemlubricating oil or in a mixture of the oil and refrigerant. The dyecompound circulates with the refrigerant and oil throughout therefrigeration circuit, and is carried out with escaping refrigerant andoil at a leak site. When the refrigeration system is exposed toultraviolet light, even a small deposit of the dye compound isbrilliantly fluorescent to allow visual detection of the leak. U.S. Pat.No. 5,149,453 discloses such a method for detecting leaks in arefrigeration system, and its content is incorporated herein byreference.

When practicing the above method of leak detection with a fluorescentdye, care has to be taken that the fluorescent dye additive is notallowed to contact the exterior of the refrigeration system as the dyeis being introduced into the system. If dye additive is inadvertentlyspilled or rubbed on the exterior of the system, it will be difficult todistinguish between fluorescence from a leak site and that resultingfrom inadvertent external contact. This is a particular concern wherethe dye additive is used for quality assurance checks of airconditioners on newly assembled automobiles, as the air conditioningsystem's final assembly is usually completed in the automobile assemblyline, after which the system is charged with refrigerant that leakdetection additive, then operated to circulate the additive and revealany leaks when viewed under ultraviolet light. While care is normallytaken to prevent the refrigerant, lubricant and dye from escaping, thenature of the assembly and charging process creates a risk of spills orinadvertent contamination on clothing or tools. Since very lowconcentration of dye is required to produce fluorescence, any dye, dyedrefrigerant or oil spilled or rubbed on the exterior of the airconditioning system may cause false leak indications.

In addition, the number of dyes that can be used are limited to thosedyes which are sufficiently soluble in order to allow the dye to beplaced in a concentrated liquid. The concentrate liquid is necessary toinject the dye into the refrigeration system. Furthermore, theconcentrated liquid must have a sufficient concentration of the dye tobe adequately fluorescent under ultra-violet illumination when mixedwith the entire refrigeration system.

Consequently, it would be desirable to have a method of introducing leakdetection dye into the air conditioning system prior to the initialcharging of the system, as this expedient would virtually eliminate anypossibility of inadvertent dye contact to the exterior of the airconditioner and allow for increased selection of dyes which can be used.

For that reason, an objective and advantage of the present invention isa method by which the leak detection dye additive is installed in an airconditioning or other refrigeration system before the system is chargedwith refrigerant. The leak detection dye is released into therefrigerant immediately after the system is charged and operated, inorder to reduce the risk of inadvertent contact of the dye on theoutside of the system and yet permit quality control leak testing aftercharging, and remains in the system to permit subsequent leak detection.

Another objective and advantage of the present invention is a methodwhich allows leak detection dye additive to be installed and stored in acomponent of the air conditioning system well prior to assembly of thecomplete system.

Another objective and advantage of the present invention is a method topre-install a specific quantity of dye additive which is proportional tothe amount of initial charge of the refrigeration or system lubricant,to ensure that a predictable concentration of dye will be introduced.

Further objects, features and advantages of the present invention, willbecome apparent to those skilled in the art as the invention is morefully understood by reading the accompanying drawings and detaileddescriptions.

SUMMARY OF THE INVENTION

The present invention provides an improved method of introducing a leakdetection dye additive into an air conditioning or other refrigerationsystem. For brevity, the description of the invention is made hereinwith reference to an air conditioning system, it being understood thatit is applicable to other refrigeration systems as well.

A predetermined amount of leak detection additive is installed into acomponent of an air conditioning system. The leak detection additive issoluble in the refrigerant and the system lubricant. The airconditioning system is assembled including the component containing thepredetermined amount of the leak detection additive. The airconditioning system is charged with a refrigerant. The refrigerantcirculates in the air conditioning system to release the leak detectadditive into the refrigerant and system lubricant.

In another preferred embodiment, a substrate material which is absorbentto the dye additive is cut into a swatch which is shaped according toits intended placement in the system, and a specific amount of the dyeadditive is placed onto and absorbed into the swatch. For example, in anembodiment intended for use inside a desiccant bag, a swatch of melaminetreated polyester felt may be cut to form a circular wafer. The waferwith absorbed additive is inserted into a desiccant bag, and thedesiccant bag is then installed in a dehydrator unit of an airconditioning system. When the air conditioning system is assembled fromits components, charged with refrigerant, and operated to cycle therefrigerant and system lubricant through the system, the refrigerant andsystem lubricant flows through the desiccant bag and takes the dye intosolution.

In another embodiment, the substrate may be used as a filter component,as for example in a replaceable filter-drier cartridge, or with asolid-core drier. In this embodiment, a woven or fibrous mesh materialis cut to the shape of a filter component of the drier, and continues tofunction as a particle filter after releasing its dye additive into therefrigerant.

In another preferred embodiment, the leak detection additive has aplurality of solid particles wherein the additive has a solubility equalto or greater than 0.1% in a system lubricant. The leak detectiveadditive takes the form of a powder, a pellet or a slurry.

In a preferred embodiment, the leak detection additive is a fluorescentdye compound or composition. The solid particles leak detection dye maybe placed in a filter bag wherein the sealed filter bag is inserted intoa component of the refrigeration system.

Further objects, features and advantages of the present invention willbecome more apparent to those skilled in the art as the nature of theinvention is better understood from the accompanying drawings anddetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of illustrating the invention, the drawings show a formof the invention which is presently preferred; it being understood,however, that the invention is not limited to the precise arrangementand instrumentality shown.

FIG. 1 is a schematic illustration of a basic refrigeration system of anautomobile air conditioner, using a receiver-dehydrator between thecondenser and evaporator;

FIG. 2 is a perspective view of an automobile air conditioner systemshowing the major components as installed in an automobile;

FIG. 3 is a sectional view of a receiver-dehydrator unit havinginstalled therein a desiccant bag containing a dye-wafer according tothe invention;

FIG. 4 is a sectional view of an in-line solid core filter-dehydratorwith portions of the casing and desiccant core cut away, wherein adye-absorbed substrate is installed as a filter component;

FIG. 5 is a sectional view of a filter-dehydrator with replaceablecartridge, wherein a dye-absorbed substrate is installed as a pre-filtercomponent;

FIG. 6 is a sectional view of a receiver-dehydrator unit havinginstalled therein a desiccant bag containing a dye in pellet formaccording to the invention;

FIG. 7 is a sectional view of a receiver-dehydrator unit havinginstalled therein a desiccant bag containing a dye in powder formaccording to the invention;

FIG. 8 is a sectional view of a receiver-dehydrator unit havinginstalled therein a desiccant bag containing a dye in slurry formaccording to the invention;

FIG. 9 is a sectional view of a receiver-dehydrator unit havinginstalled therein a desiccant bag containing a dye in powder form in afilter bag according to the invention; and

FIG. 10 is a sectional view of a receiver-dehydrator unit havinginstalled therein a desiccant bag containing a dye in powder form in acapsule according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, wherein like numerals indicate like elements,FIG. 1 illustrates a basic closed refrigeration circuit 10 of anautomobile air conditioner, by which air inside the automobile is cooledand dehumidified. FIG. 2 provides greater detail of the system 10 as itis arranged in an automobile 12.

A refrigerant 14, such as R-12 or more recently R-134a, circulates underpressure in the air conditioning/refrigeration system. In each cycle,the refrigerant is caused to change phase from liquid to gas and back toliquid, absorbing heat from the passenger compartment 16 and releasingheat outside the compartment.

More specifically, the air conditioning system 10 has an evaporator unit18 where subcooled liquid refrigerant enters and is allowed to expandand absorb heat from warm air of the passenger compartment, causing therefrigerant to vaporize. The warm air of the passenger compartment 16 isconnected to the evaporator 18 via ducting, as seen in FIG. 2, such thatthe cooled and dried air is recirculated into the passenger compartment.After absorbing heat from the passenger compartment, the refrigerant gasis drawn from the evaporator by suction into a compressor 20, whichcompresses the gas, thereby raising its pressure and temperature. Thehigh-pressure hot vapor is passed through a condenser 22, in which thevapor is exposed to a large cooling-surface area by flowing through alabyrinth of finned-coils 24 over which outside air is rapidly blown totransport heat away from the vapor. The refrigerant 14 cools to thecondensation temperature, releases its heat of condensation, and changesphase back to a hot liquid, still at a high pressure. The refrigerant 14completed the cycle by passing through a thermostatic expansion valve28, which meters the high pressure liquid refrigerant 14 as a lowpressure spray into the evaporator 18.

In some systems it is necessary to reservoir the liquid refrigerantbefore it is metered through the expansion valve because the demand ofthe evaporator varies under varying conditions. In other systems it is apractice to install an accumulator between the evaporator and compressorso that no liquid can enter the compressor. In either system, watercontamination in the refrigerant can cause the water vapor to freeze atthe point of expansion, causing refrigerant flow to be blocked, and toreact with refrigerants to form acids that may cause internal damage tometal parts. Consequently, in the depicted embodiment areceiver-dehydrator, also referred to as receiver-drier, 30 is locatedbetween the condenser 22 and the evaporator 18 to reservoir therefrigerant and remove moisture from it. In other air conditionersystems, an accumulator-dehydrator may be located between the evaporatorand compressor to accumulate the refrigerant vapor and remove moisturefrom it. As shown in FIG. 3, the receiver-dehydrator 30 contains afilter 32 to remove foreign particles and a bag 40 of desiccant material34 to remove moisture from the circulating refrigerant 14.

Although not depicted, it will be understood by those skilled in the artthat desiccant bags are also used in the accumulator of a cycling clutchorifice tube (CCOT) type of automobile air conditioner, and in theValves-in-Receiver (VIR) assembly of VIR type air conditioners, and maybe found in other locations of the refrigerant circuit in other types ofrefrigeration systems. A dye-additive swatch may be placed in thedesiccant bags used with any such system.

As shown in FIG. 2, the air conditioning system components are locatedin different parts of the engine compartment 38 and attached to variousother components of the automobile. Thus, final assembly of the airconditioner usually occurs at the time of its installation into theautomobile, and the system cannot be charged with refrigerant until thispoint. When the air conditioner is assembled and installed in theautomobile, the system is evacuated to remove air and moisture prior tocharging with refrigerant. The system is charged by releasingrefrigerant under pressure from a container through the system servicevalves to enter the system.

Since the refrigerant is under considerable pressure in a container orservice hose, there is a risk of its inadvertent escape andcontamination of surroundings. The automobile assembly workers chargingthe air conditioners typically wear safety goggles, gloves andprotective clothing, and use rags to wipe valve fittings. This createsthe problem that if the exterior of the air conditioner is contaminatedby escaping refrigerant or dye during charging, or by contact withcontaminated clothing, the dye additive in the refrigerant willfluoresce under ultra-violet illumination and give false leakindications.

This invention provides a method of introducing a leak detectionadditive 48 into the air conditioning system before the system ischarged with refrigerant, but which will allow the dye to be releasedand disperse into the refrigerant immediately after the system ischarged and circulated.

A dye-containing swatch 52 is produced from a substrate material whichis absorbent to the dye additive but which does not react withrefrigerant or the system lubricant. In a preferred embodiment for useinside a desiccant bag as described above, a melamine treated 100%polyester felt mat is cut into circular disks or wafers. A meteredamount of dye additive is applied to each wafer and allowed to absorbinto the material. For this embodiment, the wafer has a circular shape3/4 of an inch in diameter and a thickness of 0.315 inch. The disk iscut such that there are no loose fibers or felt residue from the cuttingprocedure.

A specific quantity of the dye additive 48 is metered onto the wafer andallowed to absorb into the felt material to form the swatch 52. Theamount of dye additive is dependent upon the volume of refrigerant andlubricant that will be introduced into the system, the concentration ofdye in the additive, the amount of dye necessary to make leaks visible,and the amount of dye that can exist in the system without adverselyeffecting its operation.

An alternative to metering the leak detection additive 48 onto the cutdisks or wafer is to place the leak detective additive on the substratesuch that the substrate is fully saturated with leak detection additive.In this situation, the size of the substrate determines the effectiveamount of the leak detection additive. The substrate can be cut to theproper size either prior to or after placing the leak detection additiveon the substrate.

One preferred leak detection or dye additive is a fluorescent, alkylsubstituted perylene dye compound dissolved in an oil which is the sameas the system lubricating oil, or which is otherwise compatible with therefrigerant and oil, such as the AR-GLO® and FLUORO-LITE® leak detectionadditives sold by Spectronics Corporation. This dye is soluble inpolyhalogenated hydrocarbon refrigerants and fluoresces a brilliantyellow-green under illumination by long wave ultra-violet light. In anautomobile air conditioner system which has a fully-charged capacity ofthirty-three ounces of R-134a refrigerant and seven ounces of PAGlubricating oil, an amount of 0.014 ounces of AR-GLO 4/PAG® dye additiveis effective to locate leaks without adversely effecting the operationof the system. This amount, plus an additional amount that will remainon the disk, typically 10 percent, is metered onto a disk and allowed toabsorb into the disk to create the swatch 52. The tracer swatches 52 arethen packaged in quantity (usually 1000) in a sealed moisture-proof bagfor shipment to a desiccant bag manufacturer or a receiver-dehydratormanufacturer.

Prior to installing the desiccant material 34 in the receiver-dehydrator30, a tracer swatch 52 having the leak detection additive 48 is placedinto the permeable bag 40, then the particles of desiccant material 34are added, and the bag is closed to retain the particles.

The desiccant bag 40 is itself then installed in receiver-dehydrator 30.Sealed receiver-dehydrators are shipped to the automobile or engineassembly plant to be installed in the air conditioning system as it isassembled. Upon the air conditioning system 10 being fully connected, itis evacuated and then charged with its initial refrigerant 14. Uponcharging and running the system, the dye is mixed with and dissolved inthe refrigerant 14 as the refrigerant travels through the desiccant bag40.

FIG. 4 shows another embodiment of the invention. An in-line solid corefilter-dehydrator 60 may be used in a liquid refrigerant line of an airconditioning system. Circulating refrigeration liquid enters at theinlet side 62, passes through an opening 64 shaped in a solid core ofdesiccant material 66, through a fine mesh filter material 68 and ascreen filter 70, and emerges from the outlet side 72. A substrate ofrandom mesh material which is absorbent to the dye additive, but whichdoes not react with refrigerant, may be used as the filter material 68.Alternatively, a dye-containing substrate of woven or screen-meshedmaterial which is absorbent to the dye additive, but which does notreact with refrigerant, may be used as the screen filter 70.

FIG. 5 shows a filter-dehydrator unit 74 with a replaceable cartridge76. A dye-containing substrate of fabric material, such as polyesterfelt, may be used as the circumferential filter material 78 surroundingthe porous cartridge walls to act as a pre-filter after releasing itsdye to the refrigerant.

Other substrate materials, such as natural or synthetic sponge, sinteredbrass or other metals, or even the desiccant beads may be substitutedfor those described above. The substrate may have various shapes, andquantities and dimensions may be varied as desired for specificapplications.

In the above embodiments, the leak detection dye is added to a componentof the system 10 as part of a liquid leak detection additive 48. Theadditive 48 typically includes a dye compound dissolved in solvents,including the refrigeration lubricant (also referred to as systemlubricant). The following embodiments illustrate a leak detection dye 50being added to the component of .[.to.]. the system 10 as a solid orslurry.

Referring to FIG. 6, the receiver-dehydrator 30 contains a filter 32 toremove foreign particles, and a permeable bag 40 of desiccant materials34 to remove moisture from the circulating refrigerant 14. In addition16 the desiccant materials 34, the permeable bag 40 has a pellet 80formed of leak detection dye 50. The pellet 80 may also include inertingredients.

The size of the pellet 80 is selected to provide the proper amount ofdye 50 proportional to the volume of refrigerant and lubricant that willbe introduced into the system, the concentration of dye necessary tomake leaks visible, and the amount of the dye that can exist in thesystem without adversely effecting its operation.

The particles of desiccant material 34 can be added either prior toand/or after the insertion of the pellet 80. The bag 40 is closed toretain both the particles and the pellet 80.

Similarly to the previous embodiments, the desiccant bag 40 is itselfinstalled in the receiver-dehydrator 30. Upon the air conditioner system10 being fully connected, it is evacuated and then charged with itsinitial refrigerant 14. Upon charging and running the system, the dye 50is mixed with and dissolved in the refrigerant 40 as the refrigeranttravels to the desiccant bag 40.

It is recognized that the pellet 80 can be placed in other locations inthe system 10, such as another component besides the.[.received-dehydrator.]. .Iadd.receiver-dehydrator .Iaddend.30. It ispreferred that movement of the pellet 80 through the system be preventedprior to the pellet 80 dissolving into the refrigerant and lubricant.

In contrast to a dye dissolved in liquid leak detection additives 48, asolid dye compound need only have a solubility of 0.1 percent in thesystem lubricant. In normal liquid leak detection additives, the dyeconcentrations are in the range typically of 15%-50%, in varioussolvents, including the system lubricant. While the solubility of theparticular dye compound used as a solid dye might be less than that ofanother dye used in a liquid dye additives, the resulting concentrationof dye in the system 10 might be greater.

For example, the amount metered of leak detection additive in a liquidsystem is typically about 0.03 ounces. If a 25% concentrate of dye inthe leak detection additive was used, the total amount of dye would be0.0075 ounces. If the fully charged system had 10 ounces of systemlubricant and a dye with a solubility of 0.1 percent 0.01 ounces of dyein solid form could be introduced into the system and would go intosolution upon charging and circulating the system. Therefore, a lowersolubility dye could be used, yet result in a higher dye concentration.While the amount of dye that can be introduced is calculated upon thesolubility of the dye in the system lubricant, it should be recognizedthat the dye needs to also be soluble in the refrigerant.

In a preferred embodiment, the dye is a fluorescent dye which is a solidcompound or composition soluble in both the refrigerant andrefrigeration or system lubricant. The dyes could be naphthoxanthene,perylene and naphthalene compounds, such as

Naphtho-{3,2,1-k1}xanthene-2,8-dialkyl

3,9-perylenedialkylacetate

4-alkylamino-n-alkyl-naphthalimide

Dinaphtho(1,2,3-cd; 1'2'3-1m)perylene-9,18-dione, alkyl derivatives.

Similar to the liquid dyes, the fluorescent solid dye must be stable atoperating temperatures of the A/C or refrigeration system, and shouldnot change the properties of the refrigerant or the system lubricant oradversely effect components and parts of the system.

Referring to FIG. 7, a leak detection dye 50 in a powder form 82 isadded to the permeable bag 40 along with the particles of desiccantmaterial 34. The sealed permeable bag 40 is installed in thereceiver-hydrator 30. The dye 50 in powder form 82 dissolves into thesystem 10 as the system 10 is charged.

Referring to FIG. 8, the receiver-dehydrator 30 is shown having a leakdetection dye 50 in a slurry form 84. The slurry form 84 could includeinert ingredients. The dye 50 in both the powder form 82 and the slurryform 84 is installed in a quantity dependent on the factors listed abovewith respect to the swatch 52 and the pellet 80.

In an embodiment using naphthalimide dye in a system having seven (7)ounces of PAG lubricant oil with a desired 375:1 dilution ratio and thenaphthalimide having a 25% colorant, 0.0187 ounces of liquid dyeadditive would be required and only 0.0047 ounces (volume) of powder dyewould be required. The powder dye could be added directly with theparticles of desiccant material 34 to the permeable bag 40 as in FIG. 7.In the alternative, the powder dye could be mixed with a sufficientquantity of inert binding agent to form a convenient sized tablet as inFIG. 6. Another alternative is to mix the naphthalimide dye powder witha sufficient quality of the PAG lubricant to form a slurry. The slurrymixture could be added directly into the permeable bag 40 as in FIG. 8.

Referring to FIG. 9, an alterative embodiment to installing the leakdetection dye 50 into the permeable bag 40 is to place the leakdetection dye 50 such as in the powder form 82 into a filter bag 90. Thefilter bag 90 is sealed and then placed into the permeable bag 40 alongwith the particles desiccant material 34. It is recognized that thefilter bag 90 can be placed in other components of the system 10.

Referring to FIG. 10, an alternative embodiment to installing the leakdetection dye 50 into the permeable bag 40 is to place the leakdetection dye 50 such as in the powder form 82 into a capsule 94. Thecapsule 94 is placed into the permeable bag 40 along with the particlesdesiccant material 34. The capsule 94 is formed of inert ingredientswhich dissolve in the system lubricant upon charging the system 10without adversely effecting the operation of the system 10. It isrecognized that the capsule 94 can be placed in other components of thesystem 10. Furthermore, it is recognized that the capsule 94 couldcontain the dye 50 in solid or slurry form also.

The invention may be embodied in other specific forms without departingfrom the spirit or central attributes thereof. Various dye additives maybe used, in particular, additives prepared from a fluorescentalkyl-substituted naphthalimide dye compound which fluoresce brightgreen under long-wave ultraviolet irradiation. Accordingly, referenceshould be made to the claims, rather than to the foregoingspecification, as indicating the scope of the invention.

What is claimed is:
 1. A method of introducing a leak detection additiveinto a refrigeration system in which a refrigerant and a systemlubricant are circulated, comprising the steps of:installing apredetermined amount of a leak detection additive, which is soluble inthe refrigerant and the system lubricant in a dehydrator component ofthe refrigeration system through which refrigerant circulates when thesystem is assembled and operated; assembling the refrigeration system toinclude dehydrator component; charging the refrigeration system with arefrigerant; and circulating the refrigerant in the refrigeration systemto release the leak detection additive into the refrigerant and thesystem lubricant.
 2. A method as in claim 1, wherein the step ofinstalling the leak detection additive in a dehydrator component of therefrigeration system is performed by the sub-steps of:inserting the leakdetection additive in a desiccant bag, and inserting the desiccant bagin a dehydrator component of the refrigeration system where water isremoved from the refrigerant.
 3. A method of introducing a leakdetection additive into a refrigeration system in which a refrigerantand a system lubricant are circulated, comprising the steps of:providinga substrate of material which is capable of absorbing and releasing aleak detection additive; fully saturating the substrate with leakdetection additive, which is soluble in the refrigerant and the systemlubricant, and allowing the additive to absorb into the substrate;sizing the substrate to contain an effective amount of the leakdetection additive; installing the additive-absorbed substrate in acomponent of the refrigeration system through which refrigerantcirculates when the system is assembled and operated; assembling therefrigeration system to include the component containing theadditive-absorbed substrate; charging the refrigeration system with arefrigerant; and circulating the refrigerant in the refrigeration systemto release the leak detection additive into the refrigerant and thesystem lubricant.
 4. A method as in claim 3, wherein the substrate iscut to the proper size prior to placing the leak detection additive onthe substrate.
 5. A method as in claim 3, wherein the substrate is cutto the proper size after placing the leak detection additive on thesubstrate.
 6. A method of introducing a leak detection additive into arefrigeration system in which a refrigerant and a system lubricant arecirculated, comprising the steps of:providing a leak detection additivehaving at least a plurality of solid particles; installing the leakdetection additive in a dehydrator component of the refrigeration systemthrough which refrigerant circulates when the system is assembled andoperated; assembling the refrigeration system to include the componentcontaining the leak detection additive; charging the refrigerationsystem with a refrigerant; and circulating the refrigerant and thesystem lubricant in the refrigeration system to dissolve the leakdetection additive including the particles in the refrigerant and thesystem lubricant therein releasing the leak detection additive into therefrigerant and the system lubricant.
 7. A method as in claim 6, whereinthe step of installing .[.the substrate.]. .Iadd.the leak detectionadditive .Iaddend.in a dehydrator component of the refrigeration systemis performed by the sub-steps of:inserting the leak detection additivein a filter bag; sealing the filter bag; and inserting the filter bag ina dehydrator component of the refrigeration system.
 8. A method as inclaim 6, wherein the leak detection additive is in a pellet form and thesolid particles form the pellet.
 9. A method as in claim 8, wherein thepellet comprises a powdered dye concentrate and inert ingredients.
 10. Amethod as in claim 8, wherein the pellet consists essentially ofpowdered dye concentrate.
 11. A method as in claim 6, wherein the leakdetection additive is in slurry form.
 12. A method as in claim 6,wherein the leak detection additive is in powder form.
 13. A method asin claim 6, wherein the leak detection additive includes a fluorescentdye compound which is soluble in the refrigerant and system lubricant.14. A method as in claim 13, wherein the dye compound comprises afluorescent, alkyl substituted perylene dye.
 15. A method as in claim13, wherein the dye compound comprises a fluorescent, alkyl substitutednaphthalimide dye.
 16. A method as in claim 6, wherein the step ofinstalling .[.the substrate.]. .Iadd.the leak detection additive.Iaddend.in a dehydrator component of the refrigeration system isperformed by the sub-steps of:inserting the leak detection additive in acapsule, the capsule being inert and soluble in the system lubricant;and inserting the capsule in a dehydrator component of the refrigerationsystem. .Iadd.
 17. A method of introducing a leak detection additiveinto a refrigeration system in which a refrigerant and a systemlubricant are circulated, the system having a compressor and at leastone filter for preventing solid particles from passing into thecompressor, comprising the steps of:providing a leak detection additivehaving solid particles; installing the leak detection additive, beforethe system is assembled and operated, in a component of therefrigeration system that is upstream of said filter relative to thecompressor in the refrigerant circulation; assembling the refrigerationsystem to include the component containing the leak detection additive;charging the refrigeration system with a refrigerant; and circulatingthe refrigerant and the system lubricant in the refrigerations system todissolve the leak detection additive in the refrigerant and the systemlubricant, wherein said filter restrains undissolved leak detectionadditive particles from passing into the compressor..Iaddend..Iadd.18. Amethod as in claim 17, wherein the filter is in a dehydrator componentof the system..Iaddend..Iadd.19. A method as in claim 17, wherein leakdetection additive is installed in an evaporator component of thesystem..Iaddend..Iadd.20. A method as in claim 17, wherein leakdetection additive is installed in a compressor component of thesystem..Iaddend..Iadd.21. A method as in claim 17, wherein the filter isin a condensor component of the system..Iaddend..Iadd.22. A method ofintroducing a leak detection additive into a refrigeration system inwhich a refrigerant and system lubricant are circulated, comprising thesteps of:providing a leak detection additive having solid particles;placing the leak detection additive in a restraining structure forrestraining undissolved particles from circulating with the refrigerantand system lubricant; installing the restraining structure, before thesystem is assembled and operated, in a component of the refrigerationsystem through which refrigerant circulates when the system is assembledand operated; assembling the refrigeration system to include thecomponent containing the leak detection additive and restrainingstructure; charging the refrigeration system with a refrigerant; andcirculating the refrigerant and the system lubricant in therefrigeration system to dissolve the leak detection additive in therefrigerant and the system lubricant, wherein the restraining structurerestrains undissolved leak detection particles from circulating with therefrigerant and system lubricant..Iaddend..Iadd.23. A method as in claim22, wherein the restraining structure is a fine meshbag..Iaddend..Iadd.24. A method as in claim 22, wherein the restrainingstructure is a cannister with fine mesh openings. .Iadd.25. A method ofintroducing a leak additive into a refrigeration system in which arefrigerant and a system lubricant are circulated, the system having acomponent with a restraining structure that can restrain undissolvedsolid particles from circulating with the refrigerant and systemlubricant, comprising the steps of: providing a leak detection additivehaving solid particles; installing the leak detection additive in therestraining structure of said component before the system is assembledand operated; assembling the refrigeration system to include thecomponent containing the leak detection additive; charging therefrigeration system with a refrigerant; and circulating the refrigerantand the system lubricant in the refrigeration system to dissolve thesolid particles and release the leak detection additive in therefrigerant and the system lubricant..Iaddend..Iadd.26. A method as inclaim 25, wherein the component is a condenser..Iaddend..Iadd.27. Amethod as in claim 25, wherein the component is anevaporator..Iaddend..Iadd.28. A method as in claim 25, wherein thecomponent is a compressor..Iaddend.